Smoke control device

ABSTRACT

After burner for burning combustible particles in smoke and exhaust gases from stationary installations. A heater is disposed adjacent an intake opening of a water cooled combustion chamber and brings the smoke to its combustion temperature. Particulate matter is removed from the smoke by filters before the clean, non-polluting gas is discharged to the atmosphere. Surfaces of the combustion chamber contacted by smoke or cooling water are coated with Teflon to inhibit substantially all accumulation of particulate matter on such surfaces and prevent clogging of the device. The chamber can be mounted on top of a smoke discharging stack or device or it can be placed on the ground and provided with suitable conduits and blowers for passing the smoke to and through the combustion chamber. Openings are provided to supply the necessary additional combustion air to the combustion chamber.

United States Patent [1 1 Barba 1 Jan. 9, 1973 SMOKE CONTROL DEVICE [57] ABSTRACT [75] Inventor: John J. Barba, North Anderson, After burner for burning combustible particles in Calif. smoke and exhaust gases from stationary installations. l A heater is disposed adjacent an intake opening of a [73] Asslgnees' Larry Olesen water cooled combustion chamber and brings the Alhambra, Calif.

smoke to its combustion temperature. Particulate [22] Filed: July 6, 1971 matter is removed from the smoke by filters before the clean, non-polluting gas is discharged to the at- [21] Appl 159313 mosphere. Surfaces of the combustion chamber contacted by smoke or cooling water are coated with [52] US. Cl. ..110/8 R, 110/8 A Teflon to inhibit substantially all accumulation of par- [51] Int. Cl. ..F23g 5/00 ticulate matter on such surfaces and prevent clogging [58] Field of Search 10/8, 8 A; 23/277 C of the device. The chamber can be mounted on top of a smoke discharging stack or device or it can be [56] References Cited placed on the ground and provided with suitable conduits and blowers for passing the smoke to and UNITED STATES PATENTS through the combustion chamber. Openings are pro- 3,567,399 3/1971 Altmann etal ..ll0/8 vide to supply the necessary additional combustion 3,534,693 l0/l970 Sugano ..110/10 air to the combustion chamber. 3,310,009 3/1967 Jacobs ..llO/8 3,355,254 11/1967 Hoskinson ..llO/8 X 23 Claims, 4 Drawing Figures YAYKY VAY/AYAY PATENTEDJAM ems 3,709,171

SHEET 2 [1F 2 m ,1 III II II III I/IY/ 1 III 1 1 FUEL I {J 56 FIG 2 INVENTOR.

JOHN J. BARBA 50 I W l ATTORNEYS SMOKE CONTROL DEVICE BACKGROUND OF THE INVENTION Smoke and particularly unburned subject matter or combustible materials in the smoke from furnaces, incinerators, wood burning tepees and similar stationary installations is the source of a substantial portion of todays alarmingly increasing air pollution. If such unburned materials could be combusted or incinerated before they escape to the atmosphere the thus discharged fully combusted smoke or gas would cease to be a pollutant provided all particulate matter in the gas such as dust, flying ash and the like is also removed. The latter is done in suitable filters. The combustion of combustible materials, however, encompasses significant problems.

Such combustion must be carried on in a secondary combustion zone or chamber or an after burner downstream of the main combustion zone. To achieve combustion the temperature of the smoke must usually be significantly raised and additional air must be introduced to sustain the secondary combustion. Also, significant heat is generated which heretofore caused the greatest problems. I

To withstand the heat it is often required to build an after burner which is more expensive than the main combustion chamber. Failure to do so can render it impossible to substantially completely combust unburned materials or, alternatively would overheat the after burner and damage or destroy it in a short period. The expense of constructing such after burners has, therefore, often been considered prohibitive so that pollutants continue to be discharged to the atmosphere.

The increasing strictness of laws and regulations concerning the discharge of pollutants and exhaust gases of stationary installations now forces the operators of such installations to the verge of expending large amounts of monies to install the expensive prior art smoke after burners. Frequently, the operators are unable to comply with the newly enacted regulations and must resort to expensive alternatives such as eliminating the burning operation altogether and burying the heretofore incinerated materials. This requires trucking, burying grounds and can cost the operators several hundred dollars a day.

SUMMARY OF THE INVENTION 'The present invention provides an after burner for stationary smoke emitting installations which is relatively inexpensive to construct and which can even yield economic returns from recovered heat energy. The after burner is readily adapted for use with virtually all stationary smoke emitting installations. Generally speaking, an after burner constructed in accordance with the invention comprises a tubular member which defines a combustion chamber having an inlet thereto and an outlet therefrom for passing exhaust gas therethrough. A heater adjacent the inlet brings the exhaust gas entering the chamber to its combustion temperature. An outer shell is disposed about the tubular inner member, is sealingly secured thereto and defining a water jacket surrounding the member. Means is also provided for flowing cooling water through the jacket to maintain the temperature of the member sufficiently low to prevent damage thereto from the exhaust gas combustion temperature in the chamber. Burner surfaces that come in contact with smoke or cooling water are coated with a material such as synthetic resin polymer and the like, available under the trademark Teflon for example, which inhibits the adherence of substances such as dust, ash, carbon, calcium and the like to such burner surfaces.

The after burner of the invention can be placed directly on top of a stack or like smoke discharging opening of an existing installation by mounting it directly to such installation or supporting it independently thereof directly on the ground. When so installed the after burner is in an upright position with the combustion chamber intake disposed vertically above the smoke stack. A downwardly extending and outwardly flaring apron extends to below the stack discharge opening and is prefarably spaced from the stack to provide an air intake gap for the required additional combustion air. The air is directly guided into the combustion chamber for admixture with the smoke and heating to the combustion temperature.

The after burner can be readily installed independently of the smoke stack or the like by simply providing a tripod like support structure. It needs little or no custom fitting so that the after burner can be mass produced, is available at relatively low cost and can be used with virtually any existing or new installation.

Another manner of installing the after burner of the invention is to place it on the ground. A smoke conduit connects the smoke emitting opening with the combustion chamber inlet. To assure a uniform and continuous smoke flow a blower is disposed upstream of the chamber intake. In terms of operation the after burner functions in the same manner as one that is installed vertically above the smoke stack. To enable continued operation of the smoke emitting installation even in cases of power failures or failures in the operation of the smoke blower, which in some parts of the country and especially rural areas during adverse weather conditions is a problem of considerable proportions,'a vent door is provided in the smoke conduit upstream of the blower. During normal operation the pressure differential between the atmosphere and the vacuumized smoke upstream of the blower biases the door in a closed position. When the blower fails to operate the pressure in the conduit equalizes with the atmosphere thereby permitting a spring or like device to open the door so that smoke can escape to the atmosphere until the blower can be returned to operation.

The after burner of the present invention is of a simple construction, contains no moving parts and is virtually maintenance free.

Particulate matter such ad dust, ash and the like is prevented from adhering to the Teflon or the like coating facing the combustion chamber and mineral deposits from the cooling water are prevented from adhering to interior sides of the water jacket surrounding the combustion chamber. The cooling water maintains the temperature of the combustion chamber walls relatively low to prevent damage to the coating and the after burner itself even though the gas temperature in the combustion chamberis high. The after burner is further readily adapted for use with smoke emitting installations emitting relatively large smoke volumes since the diameter and length of the combustion chamber can be readily increased.

In operation the cooling water does not become contaminated so that it can be used for any desiredpurpose. Moreover, heat energy in the water can be employed for industrial applications, heating or the like. Lastly, steam coils can be placed into the combustion chamber to recoup further heat energy for such applications as the generation of electricity or the like. In this manner operation of the after burner of the present invention can actually result in economic gain as compared to the potentially large costs of terminating the incineration of products such as waste due to excessive air pollution and replacing the incineration with expensive burying.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic, side elevational view of a smoke after burner constructed in accordance with the present invention, placed vertically above a smoke emitting installation and independently supported on the ground;

FIG. 2 is a fragmentary, enlarged side elevational view, in section, of an after burner constructed in accordance with the invention;

FIG. 3 is a front elevational view, in section, of the burner shown in FIG. 2 and is taken on line 3-3 of FIG. 2; and

FIG. 4 is a schematic side elevational view of another installation of the smoke after burner of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1, a fixed smoke emitting installation such as a waste product incinerator 8 includes a smoke stack 10 that terminates in a smoke emitting opening 12. Placed over the stack is a smoke after burner 14 constructed in accordance with the invention. The after burner rests on a platform 16 supported by a tripod 18 anchored to foundation blocks 20 in ground 22. The illustrated incinerator can of course be replaced by another installation such as a curbed burning tepee (not shown in FIG. 1

Referring now to FIGS. 1 through 3, after burner 14 generally comprises a pair of tubular and preferably cylindrically tubular inner and outer members 24 and 26 interconnected by face plates 28 and defining an elongated, cylindrical combustion chamber .30 surrounded by an annular water jacket 32 surrounding and extending over-the length of the combustion chamber. A ring heater or burner 34 with a pilot light 35 is positioned adjacent intake 36 of the chamber. Smoke is flowed into the chamber through suitable conduit means such as duct 38 shown in FIG. 2. The ring burner assures that all gas entering through intake 36 is substantially uniformly heated for the substantially uniform combustion of all combustible materials in the smoke. The smoke is withdrawn from the chamber via a chamber outlet 40, passes into a discharge conduit 42 and hence to the atmosphere. Conventional filters44 such as scrubbers (water spray filters) and dry filters are disposed between the end of discharge conduit 42 and outlet to remove particulate matter from the gases before they are discharged into the atmosphere.

Referring now specifically to FIGS. 2 and 3, tubes 24 and 26 are constructed of steel plates, standard tubing or the like and are securely fastened together as by welding face plates 28 thereto. Spaced over the length of water jacket 32 are a plurality of annular baflle plates 46 secured to one of the tubes, preferably the inner tube 24, and spaced from the other tube, preferably from the outer tube 26, a short distance to prevent a direct heat transfer between the tubes while substantially completely separating the water jacket into a plurality of axially distributed water sections 48. Cooling water is supplied to the water jacket from supply pipe 50 and individually distributed to each water jacket section 48 via intake pipes 52. Similarly, warm coolant is withdrawn from the individual sections via outlet pipes 54 that terminate in warm water discharge pipe 56.

In operation smoke is flowed to combustion chamber 30 through duct 38. When it passes ring burner 34 the temperature of the smokeis sufficiently elevated so that all combustible materials in the smoke are burned. To assure complete burning of combustible materials additional air is supplied via air intake holes 58 in duct 38. The smoke temperature in the combustion chamber is sufficiently high, a sufficient amount of air is supplied and the combustion chamber is of a sufficient length so that when the smoke arrives at outlet 40 substantially all combustible materials have been incinerated. Solids are filtered out by filters 44 and the non-polluting, smokeless exhaust gas is discharged to the atmosphere.

The provision of a plurality of water jacket sections distributed over the length of the combustion chamber maintains the sections at substantially the same temperature. Temperature variations in the chamber from differences in the temperature of the coolant prevent local overheating and undesirable variations in the smoke incineration rate.

To eliminate virtually all need for maintenance of the after burner the surfaces of the burner that contact either smoke or water are treated to inhibit or eliminate the adherence of particulate matter to such surfaces. It is presently preferred to apply a coat 60 of Teflon or a like material to the interior and exterior surfaces of inner tube 24, to the interior surface of outer tube 26, to the inwardly facing sides of face plates 28, and to all sides of baffle plates 46 exposed to cooling water. This prevents dust, dirt, carbon or ash deposits onthe walls of combustion chamber 30 and mineral deposits such as calcium deposits on the walls of water jacket 32. The after burner, therefore, needs virtually no cleaning and, therefore, no maintenance for trouble free operation.

For the recovery of heat energy warm cooling water withdrawn from the after burner 14 can be used for heating or .industrial purposes. Moreover, a steam coil 62 can be placed into an aft portion .of combustion chamber 30 and connected to warm water discharge pipe 56 (or a separate water pipe) for generating steam that'can then be commercially used as for the production of electricity with a steam generator. The costs of operating a smoke after burner can thereby be greatly reduced or transformed into profits from heat energy recouped from the after bumer.

Referring again to FIG. 1 only, when after burner 14 is installed in an upright position just above a smoke stack, a conical, downwardly extending, outwardly flared apron 64 is secured to the after burner and guides smoke discharged by stack 10 into combustion chamber 30. The apron extends below stack opening 12 and has a diameter greater than the diameter of the stack to define an annular gap 66 through which additional combustion air is automatically drawn by the reduced pressure of the upwardly flowing smoke. This manner of installing the after burner thus requires no additional equipment such as fresh air and/or smoke blowers and the like.

Referring now to FIG. 4, smoke after burner 14 can also be installed on the ground in either a horizontal or an upright position. In FIG. 4 the after burner is illustrated in combination with a conventional wood buming tepee 68 to which a hood 70 is sealed and which connects with a smoke duct or conduit 72. The conduit leads downwardly from the top of the tepee to intake 36 of the after burner. To assure continuous and uniform smoke flow a conventional blower 74 is disposed upstream of the after burner. A filter room 76 having dry filters 78 and conventional water filters 80 is downstream of the combustion chamber and terminates in an exhaust conduit 82. If required an exhaust fan 84 that is synchronized with smoke blower 74 to prevent pressure or vacuum build-ups in the after burner or the filter room is provided for high capacity exhaust discharge. As in the foregoing case the exhaust gas comprises non-polluting substantially fully combusted gas free of particulate matter.

Smoke conduit 72 includes a smoke venting emergency opening normally closed by a door 86 that is sealed to the conduit and pressed thereagainst by the pressure differential between the atmosphere and the vacuum present in the conduit as long as blower 74 is operating. Should the blower stop the vacuum in the smoke conduit is lost. Means such as a spring (schematically illustrated at 88 in FIG. 4) then automatically opens door 86 to permit smoke from tepee 68 to escape to the atmosphere until the smoke blower can be placed into operation again. Upon actuation of the smoke blower door 86 is closed as by pulling a suitably mounted chain 90 that forces the door in opposition to spring 88 into a closed position whereupon the door remains closed by virtue of the pressure difierential.

I claim:

1. Apparatus for burning combustible material in the exhaust gas of a furnace, an incinerator, or the like for the discharge into the atmosphere of substantially completely combusted, non-polluting gas, the apparatus comprising: a tubular member defining a combustion chamber, an inlet thereto and an outlet therefrom for passing exhaust gas therethrough, burner means adjacent the inlet for heating the exhaust gas entering the chamber to its combustion temperature, means applied to a surface of the tubular member inhibiting the build-up of particulate matter on such surface, an outer shell disposed about the member, sealingly secured thereto and defining a jacket surrounding the member, and means for flowing a coolant through the jacket maintaining the temperature of the member sufficiently low to prevent damage thereto from the exhaust gas combustion temperature in the chamber.

2. Apparatus according to claim 1 wherein the buildup inhibiting means comprises a Teflon coat applied to a side of the member facing the combustion chamber to prevent the adherence of particulate matter to such side.

3. Apparatus according to claim 1 wherein the buildup inhibiting means comprises a Teflon coat applied to a side of the member facing the shell, and including a Teflon coat on surfaces of the shell facing the jacket to prevent the build-up of particulate matter and an eventual plugging of the jacket by such particulate matter.

4. Apparatus according to claim 3 including baffle means defining a plurality of substantially separate jacket sections,. and wherein the means for flowing water comprises means for independently flowing water into and from each such section.

5. Apparatus according to claim 4 wherein the baffle means comprises plate means surrounding a periphery of the member and disposed between axial ends of the jacket. 7

6. Apparatus according to claim 5 wherein each plate means is secured to one of the member and the shell and spaced from the other one of the member and the shell to prevent a direct heat transfer from the member to the shell and to thus maintain the shell at a temperature substantially equal to-the temperature of the water in the jacket during the combustion of exhaust gas.

7. Apparatus according to claim 6 including a Teflon coat on all surfaces of the plate means contacted by the water.

8. A smoke burner for substantially completely burning combustible materials in exhaust gases comprising: substantially concentric inner and outer tubular members sealingly secured to each other and defining a central axially extending combustion chamber and a water jacket between which fully surrounds the chamber, a plurality of substantially annular baffle plates disposed in the jacket secured to the inner member, spaced over the length of the chamber and defining a plurality of jacket sections, a periphery of the baffle plates being spaced from the outer member to prevent a direct heat transfer between them, a cooling water inlet and outlet for each jacket section to independently flow cooling water therethrough and for maintaining the inner member at a substantially uniform temperature throughout its length, a burner at one end of the chamber for heating the exhaust gas to its combustion temperature, filter means adjacent another end of the chamber for the removal of particulate matter from the substantially fully combusted exhaust gas befor discharge of the gas to the atmosphere, means for connecting the one end of the combustion chamber with a smoke discharging opening for flowing the smoke past the burner'into the combustion chamber, and means applied to surfacesof the inner and the outer members and of the baffle plates exposed to the combustion chamber or the jacket for inhibiting the build-up of particulate matter on such surfaces to prevent clogging of the chamber or the jacket with such particulate matter.

9. Apparatus according to claim 8 wherein the smoke discharging opening is an upwardly facing opening, wherein the members are disposed above the opening in substantially vertical alignment therewith with the one end of the chamber adjacent the opening, including means for supporting the members in such position, and wherein the smoke flowing means comprises a conically shaped apron communicating with the one combustion chamber end, and extending downwardly and outwardly therefrom past the smoke discharging opening to form an annular gap between the apron and the smoke discharge opening for the supply of air needed in the combustion of the smoke.

10. Apparatus according to claim 9 wherein the member supporting means comprises frame means supporting the members directly on the ground.

11. Apparatus according to claim 8 wherein the members are disposed below the smoke discharge opening, wherein the smoke flowing means comprises conduit means connecting the opening with the one combustion chamber end, and including means for inducing a smoke flow from the opening to the one combustion chamber end.

12. Apparatus according to claim 11 wherein the smoke flow inducing means comprises blower means disposed between the opening and the combustion chamber.

13. Apparatus according to claim 12 including second blower means disposed upstream of the combustion chamber for inducing a flow of combusted exhaust smoke to the atmosphere.

14. Apparatus according to claim 13 including filter means between the combustion chamber and the second blower means for the removal of particulate matter from the combusted smoke before its discharge to the atmosphere, and wherein the first and second blower means operate in synchronism to prevent the formation of substantial pressure differentials between them. 1

15. Apparatus according to claim 11 including means for automatically venting the conduit means to the atmosphere in response to a failure of the blower means for the automatic emergency discharge of smoke to the atmosphere.

16. Apparatus according to claim 15 wherein the automatic vent means comprises door means disposed upstream of the blower means, means sealing the door means to the conduit means so that a pressure differential between the atmosphere and the conduit means maintains the door means closed, and means for biasing the door means in opposition to such pressure differential into an openposition with a force that is less than the force resulting from the pressure differential so that failure of the blower means automatically opens the door means for the escape of smoke to the atmosphere.

17. Apparatus according -,to claim 16 including means for closing the door means in opposition to the means biasing the door means into an open position.

18. Apparatus according to' claim 8 wherein the burner comprises a ring burner disposed closely adjacent the first member so that smoke entering the combustion chamber passes therethrough for substantially uniform heating and burning of materials. 7

19. Apparatus for preventing the discharge of incompletely combusted smoke into a resulting pollution of the atmosphere, the apparatus comprising: a water cooled, elongated smoke burner having an inlet and an outlet and a coating inhibiting the build-up of particulate matter on all surfaces contacted by the smoke or the water, means for maintaining the temperature of a surface facing the smoke in the burner substantiallyuniform over the length of the burner, means adjacent an inlet of the burner for heating the smoke to its combustion temperature, means for admitting additional combustion air into the smoke to assure its complete combustion, means for guiding smoke from a smoke discharge opening to the burner, and means for discharging into the atmosphere the combusted smoke.

20. Apparatus according to claim 19 including a.

steam coil disposed in the burner for generating steam from heat energy in the smoke.

21. Apparatus according to claim 20 including means for passing warm cooling water into the steam coil for the utilization of heat energy .in the cooling water in the subsequent steam generation.

22. Apparatus according to claim 19 wherein the smoke discharging opening comprises an upper end of wood burning tepee, wherein the burner is substantially vertically oriented and positioned on top of the tepee with the inlet adjoining the upper tepee end, and wherein the means for guiding the smoke into the burner comprises an outwardly and downwardly oriented apron connected to the burner adjacent the inlet, extending over the upper tepee end, and spaced from the tepee end to define a gap comprising the means for the admission of additional combustion air, and including means for supporting the burner.

23. Apparatus according to claim 22 wherein the supporting means includes means for supporting the burner independently of the tepee on the ground. 

1. Apparatus for burning combustible material in the exhaust gas of a furnace, an incinerator, or the like for the discharge into the atmosphere of substantially completely combusted, nonpolluting gas, the apparatus comprising: a tubular member defining a combustion chamber, an inlet thereto and an outlet therefrom for passing exhaust gas therethrough, burner means adjacent the inlet for heating the exhaust gas entering the chamber to its combustion temperature, means applied to a surface of the tubular member inhibiting the build-up of particulate matter on such surface, an outer shell disposed about the member, sealingly secured thereto and defining a jacket surrounding the member, and means for flowing a coolant through the jacket maintaining the temperature of the member sufficiently low to prevent damage thereto from the exhaust gas combustion temperature in the chamber.
 2. Apparatus according to claim 1 wherein the build-up inhibiting means comprises a Teflon coat applied to a side of the member facing the combustion chamber to prevent the adherence of particulate matter to such side.
 3. Apparatus according to claim 1 wherein the build-up inhibiting means comprises a Teflon coat applied to a side of the member facing the shell, and including a Teflon coat on surfaces of the shell facing the jacket to prevent the build-up of particulate matter and an eventual plugging of the jacket by such particulate matter.
 4. Apparatus according to claim 3 including baffle means defining a plurality of substantially separate jacket sections, and wherein the means for flowing water comprises means for independently flowing water into and from each such section.
 5. Apparatus according to claim 4 wherein the baffle means comprises plate means surrounding a periphery of the member and disposed between axial ends of the jacket.
 6. Apparatus according to claim 5 wherein each plate means is secured to one of the member and the shell and spaced from the other one of the member and the shell to prevent a direct heat transfer from the member to the shell and to thus maintain the shell at a temperature substantially equal to the temperature of the water in the jacket during the combustion of exhaust gas.
 7. Apparatus according to claim 6 including a Teflon coat on all surfaces of the plate means contacted by the water.
 8. A smoke burner for substantially completely burning combustible materials in exhaust gases comprising: substantially concentric inner and outer tubular members sealingly secured to each other and defining a central axially extending combustion chamber and a water jacket between which fully surrounds the chamber, a plurality of substantially annular baffle plates disposed in the jacket secured to the inner member, spaced over the length of the chamber and defining a plurality of jacket sections, a periphery of the baffle plates being spaced from the outer member to prevent a direct heat transfer between them, a cooling water inlet and outlet for each jacket section to independently flow cooling water therethrough and for maintaining the inner member at a substantially uniform temperature throughout its length, a burner at one end of the chamber for heating the exhaust gas to its combustion temperature, filter means adjacent another end of the chamber for the removal of particulate matter from the substantially fully combusted exhaust gas befor discharge of the gas to the atmosphere, means for connecting the one end of the combustion chamber with a smoke discharging opening for flowing the smoke past the burner into the combustion chamber, and means applied to surfaces of the inner and the outer members and of the baffle plates exposed to the combustion chamber or the jacket for inhibiting the build-up of particulate matter on such surfaces to prevent clogging of the chamber or the jacket with such particulate matter.
 9. Apparatus according to claim 8 wherein the smoke discharging opening is an upwardly facing opening, wherein the members are disposed above the opening in substantially vertical alignment therewith with the one end of the chamber adjacent the opening, including means for supporting the members in such position, and wherein the smoke flowing means comprises a conically shaped apron communicating with the one combustion chamber end, and extending downwardly and outwardly therefrom past the smoke discharging opening to form an annular gap between the apron and the smoke discharge opening for the supply of air needed in the combustion of the smoke.
 10. Apparatus according to claim 9 wherein the member supporting means comprises frame means supporting the members directly on the ground.
 11. Apparatus according to claim 8 wherein the members are disposed below the smoke discharge opening, wherein the smoke flowing means comprises conduit means connecting the opening with the one combustion chamber end, and including means for inducing a smoke flow from the opening to the one combustion chamber end.
 12. Apparatus according to claim 11 wherein the smoke flow inducing means comprises blower means disposed between the opening and the combustion chamber.
 13. Apparatus according to claim 12 including second blower means disposed upstream of the combustion chamber for inducing a flow of combusted exhaust smoke to the atmosphere.
 14. Apparatus according to claim 13 including filter means between the combustion chamber and the second blower means for the removal of particulate matter from the combusted smoke before its discharge to the atmosphere, and wherein the first and second blower means operate in synchronism to prevent the formation of substantial pressure differentials between them.
 15. Apparatus according to claim 11 including means for automatically venting the conduit means to the atmosphere in response to a failure of the blower means for the automatic emergency discharge of smoke to the atmosphere.
 16. Apparatus according to claim 15 wherein the automatic vent means comprises door means disposed upstream of the blower means, means sealing the door means to the conduit means so that a pressure differential between the atmosphere and the conduit means maintains the door means closed, and means for biasing the door means in opposition to such pressure differential into an open position with a force that is less than the force resulting from the pressure differential so that failure of the blower means automatically opens the door means for the escape of smoke to the atmosphere.
 17. Apparatus according to claim 16 including means for closing the door means in opposition to the means biasing the door means into an open position.
 18. Apparatus according to claim 8 wherein the burner comprises a ring burner disposed closely adjacent the first member so that smoke entering the combustion chamber passes therethrough for substantially uniform heating and burning of materials.
 19. Apparatus for preventing the discharge of incompletely combusted smoke into a resulting pollution of the atmosphere, the apparatus comprising: a water cooled, elongated smoke burner having an inlet and an outlet and a coating inhibiting the build-up of particulate matter on all surfaces contacted by the smoke or the Water, means for maintaining the temperature of a surface facing the smoke in the burner substantially uniform over the length of the burner, means adjacent an inlet of the burner for heating the smoke to its combustion temperature, means for admitting additional combustion air into the smoke to assure its complete combustion, means for guiding smoke from a smoke discharge opening to the burner, and means for discharging into the atmosphere the combusted smoke.
 20. Apparatus according to claim 19 including a steam coil disposed in the burner for generating steam from heat energy in the smoke.
 21. Apparatus according to claim 20 including means for passing warm cooling water into the steam coil for the utilization of heat energy in the cooling water in the subsequent steam generation.
 22. Apparatus according to claim 19 wherein the smoke discharging opening comprises an upper end of wood burning tepee, wherein the burner is substantially vertically oriented and positioned on top of the tepee with the inlet adjoining the upper tepee end, and wherein the means for guiding the smoke into the burner comprises an outwardly and downwardly oriented apron connected to the burner adjacent the inlet, extending over the upper tepee end, and spaced from the tepee end to define a gap comprising the means for the admission of additional combustion air, and including means for supporting the burner.
 23. Apparatus according to claim 22 wherein the supporting means includes means for supporting the burner independently of the tepee on the ground. 